On September 24, 2025 Summit Therapeutics Inc. (NASDAQ: SMMT) ("Summit," "we," or the "Company") reported that data from the Phase III HARMONi-6 trial, conducted in China and sponsored by our partner, Akeso, Inc. (HKEX Code: 9926.HK), featuring the novel, potential first-in-class investigational bispecific antibody, ivonescimab, will be featured as part of the Presidential Symposium at the European Society for Medical Oncology 2025 Congress (ESMO 2025) which takes place from October 17–21, 2025, in Berlin, Germany (Press release, Summit Therapeutics, SEP 24, 2025, View Source [SID1234656211]). The presentation will take place on Sunday, October 19 during the Presidential Symposium from 4:30pm – 6:30pm CET (10:30am – 12:30pm EDT).
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HARMONi-6 is evaluating ivonescimab in combination with platinum-based chemotherapy compared with tislelizumab, a PD-1 inhibitor, in combination with platinum-based chemotherapy in patients with locally advanced or metastatic squamous non-small cell lung cancer (NSCLC) irrespective of PD-L1 expression. HARMONi-6 is a single region, multi-center, Phase III study conducted in China sponsored by Akeso with all relevant data exclusively generated, managed, and analyzed by Akeso.
On April 23, 2025, Akeso announced, via a press release, topline results from HARMONi-6. At a prespecified interim analysis conducted by an Independent Data Monitoring Committee, ivonescimab plus chemotherapy demonstrated a statistically significant and clinically meaningful improvement in PFS by blinded independent central radiology review committee (BICR) compared to tislelizumab plus chemotherapy. The PFS benefit was demonstrated in patients with either PD-L1-positive or PD-L1-negative tumors. Akeso noted that no new safety signals were identified in this Phase III study. Prior to HARMONi-6, there were no known Phase III clinical trials in NSCLC which have shown a statistically significant improvement compared to PD-(L)1 inhibitor therapy in combination with chemotherapy in a head-to-head setting.
The trial results will be presented by Dr. Shun Lu, MD, PhD, Chief of Shanghai Lung Cancer Center at Shanghai Chest Hospital, Professor of Medicine at Shanghai Jiaotong University, and associate editor for Journal of Thoracic Oncology, Lung Cancer, and editor for The Oncologist.
Summit is currently enrolling patients in the HARMONi-3 study. HARMONi-3 is a multiregional Phase III clinical trial sponsored by Summit which is intended to evaluate ivonescimab combined with chemotherapy compared to pembrolizumab, an anti-PD-1 antibody, combined with chemotherapy in patients with first-line metastatic, squamous and non-squamous NSCLC. HARMONi-3 is currently enrolling patients globally and is conducted with registrational intent for the United States and other regions within Summit’s license territories.
About the ESMO (Free ESMO Whitepaper) 2025 Presidential Symposium Presentation
Presidential Symposium Presentation
Presentation Title: Phase III Study of Ivonescimab plus chemotherapy versus Tislelizumab plus chemotherapy as First-line Treatment for advanced squamous non-small cell lung cancer (HARMONi-6)
Presenter: Dr. Shun Lu, MD, PhD, Chief of Shanghai Lung Cancer Center at Shanghai Chest Hospital
ESMO Presentation No.: Presidential Symposium 2, #3035
Session Date & Time: Sunday, October 19, 2025, 4:30pm – 6:30pm CET (10:30am – 12:30pm ET)
About Ivonescimab
Ivonescimab, known as SMT112 in Summit’s license territories, North America, South America, Europe, the Middle East, Africa, and Japan, and as AK112 in China and Australia, is a novel, potential first-in-class investigational bispecific antibody combining the effects of immunotherapy via a blockade of PD-1 with the anti-angiogenesis effects associated with blocking VEGF into a single molecule. Ivonescimab displays unique cooperative binding to each of its intended targets with multifold higher affinity to PD-1 when in the presence of VEGF.
This could differentiate ivonescimab as there is potentially higher expression (presence) of both PD-1 and VEGF in tumor tissue and the tumor microenvironment (TME) as compared to normal tissue in the body. Ivonescimab’s tetravalent structure (four binding sites) enables higher avidity (accumulated strength of multiple binding interactions) in the TME (Zhong, et al, SITC (Free SITC Whitepaper), 2023). This tetravalent structure, the intentional novel design of the molecule, and bringing these two targets into a single bispecific antibody with cooperative binding qualities have the potential to direct ivonescimab to the tumor tissue versus healthy tissue. The intent of this design, together with a half-life of 6 to 7 days after the first dose (Zhong, et al, SITC (Free SITC Whitepaper), 2023), is to improve upon previously established efficacy thresholds, in addition to side effects and safety profiles associated with these targets.
Ivonescimab was engineered by Akeso Inc. (HKEX Code: 9926.HK) and is currently engaged in multiple Phase III clinical trials. Over 2,800 patients have been treated with ivonescimab in clinical studies globally.
Summit began its clinical development of ivonescimab in non-small cell lung cancer (NSCLC), commencing enrollment in 2023 in two multiregional Phase III clinical trials, HARMONi and HARMONi-3. Additionally, in early 2025, the Company began enrolling patients in the United States for HARMONi-7.
HARMONi is a Phase III clinical trial which intends to evaluate ivonescimab combined with chemotherapy compared to placebo plus chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non-squamous NSCLC who have progressed after treatment with a 3rd generation EGFR TKI (e.g., osimertinib).
HARMONi-3 is a Phase III clinical trial which is intended to evaluate ivonescimab combined with chemotherapy compared to pembrolizumab combined with chemotherapy in patients with first-line metastatic, squamous or non-squamous NSCLC, irrespective of PD-L1 expression.
HARMONi-7 is a Phase III clinical trial which is intended to evaluate ivonescimab monotherapy compared to pembrolizumab monotherapy in patients with first-line metastatic NSCLC whose tumors have high PD-L1 expression.
In addition, Akeso has recently had positive read-outs in three single-region (China), randomized Phase III clinical trials for ivonescimab in NSCLC: HARMONi-A, HARMONi-2, and HARMONi-6.
HARMONi-A was a Phase III clinical trial which evaluated ivonescimab combined with chemotherapy compared to placebo plus chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non-squamous NSCLC who have progressed after treatment with an EGFR TKI.
HARMONi-2 is a Phase III clinical trial evaluating monotherapy ivonescimab against monotherapy pembrolizumab in patients with locally advanced or metastatic NSCLC whose tumors have positive PD-L1 expression.
HARMONi-6 is a Phase III clinical trial evaluating ivonescimab in combination with platinum-based chemotherapy compared with tislelizumab, an anti-PD-1 antibody, in combination with platinum-based chemotherapy in patients with locally advanced or metastatic squamous NSCLC, irrespective of PD-L1 expression.
Akeso is actively conducting multiple Phase III clinical studies in settings outside of NSCLC, including biliary tract cancer, colorectal cancer, breast cancer, pancreatic cancer, small cell lung cancer, and head and neck cancer.
Ivonescimab is an investigational therapy that is not approved by any regulatory authority in Summit’s license territories, including the United States and Europe. Ivonescimab was initially approved for marketing authorization in China in May 2024. Ivonescimab was granted Fast Track designation by the US Food & Drug Administration (FDA) for the HARMONi clinical trial setting.